Cultural and ethnic minorities tend to face more stressors quantitatively and qualitatively than the majority population and this stress is thought to contribute to health disparities. However, the links between these remain unclear. We, and others, have shown that Puerto Rican elders living in the US mainland are at particularly high risk for several conditions, including physical frailty, depression, diabetes and cognitive impairment, relative even to non-Hispanic white elders living in the same neighborhoods. Allostatic load has been proposed as a conceptualization of cumulative biological burden exacted on the body through attempt to adapt to daily physical and emotional stress. We propose to conduct a prospective cohort study of Puerto Rican adults in the greater Boston area to investigate the impact of life experiences and psychosocial stress on allostatic load as a marker of biological risk; to assess cross-sectional and two year prospective interrelationships between measures of allostatic load and depression, cognitive function and physical disability; to determine the extent of social support and assess how this moderates the above associations; and to assess vitamin intake and nutritional status and to investigate how this moderates the above associations. Based on preliminary studies and our experience with the Hispanic community, our working hypothesis is that older Puerto Ricans living in Massachusetts have experienced, to a variable degree, social and psychological stressors related to conditions of poverty, migration, acculturation, perceived discrimination, language and social isolation, and these accumulated stressors are associated with significant and progressive allostatic load. This load, in turn, is associated with greater prevalence and progression of depression, cognitive decline and physical disability. We also hypothesize that older Puerto Rican adults with strong social networks are less vulnerable to physiologic responses of allostatic load and to its effects on cognitive and physical function than those without such contacts, and that allostatic load is more pronounced and its impact on depression, cognitive decline and physical disability greater in those individuals with the poorest nutritional status.